Device for unidirectionally blocking a ratchet wheel in a clockwork movement

ABSTRACT

A device for unidirectionally blocking a ratchet wheel, comprising a unique blocking organ having on the one hand retaining means co-operating with stop means formed by stationary parts of a clockwork movement and, on the other hand, a tooth and a disengaging means, both of which co-operate with the toothing of said ratchet wheel, advantages resulting mainly in the automatic mounting of the device.

United States Patent Zaugg July 4, 1972 1541 DEVICE FOR UNIDIRECTIONALLY l,467,427 9/1923 Freund ..58/86 x BLOCKING A RATCHET WHEEL IN A 0 E CLOCKWORK MOVEMENT F R l-GN PATENTS OR APPLICATIONS 328,132 2/1958 Switzerland ..58/86 [72] lnvenw" gx' gg f Rebgasse Grenchen 256,586 8/1948 Switzerland [22] F d S 14 1970 333,249 10/1958 Switzerland 1 e 2 ept. [21] APPLNO': 71,986 Prirnary ExaminerRichard B. Wilkinson Assistant ExammerGeorge H. Miller, Jr.

Attome Stevens, Davis, Miller & Mosher [30] Foreign Application Priority Data y Sept. 15, 1969 Switzerland ..13'910/69 [571 ABSTRACT A device for unidirectionally blocking a ratchet wheel, com- [22] US. Cll ..58/86, 58/83 prising a unique blocking organ having on the one hand retaim h 5 52 23? ing means co-operating with stop means formed by stationary IE 0 care ,8 parts of a clockwork movement on the other hand, a tooth and a disengaging means, both of which co-operate with [56] References Cited the toothing of said ratchet wheel, advantages resulting mainly UNITED STATES PATENTS in the automatic mounting of the device.

1,416,407 5/1922 Horn ..58/86 7 Claims, 8 Drawing Figures P'A'TENTEB JUL 4 m2 3. 673 791 sum 2 or 5 DEVICE FOR UNIDIRECTIONALLY BLOCKING A RATCHET WHEEL IN ACLOCKWORK MOVEMENT This invention relates to devices for unidirectionally blocking a ratchet wheel, especially in clockwork or watch movements.

Prior art clockwork movements have ratchet wheels wedged on the barrel arbor and co-operating with a retaining or blocking pawl mounted on the barrel bar. Said retaining or blocking pawl is generally made up of a blanked steel member pivoting around of a screw member and which is biased by a spring wire. The pawl is generally set up so as to allow the main or motor spring of the watch movement to slacken slightly at the moment of releasing the winding button or crown and before the blocking of the ratchet wheel, wherby to avoid to keep said main or motor spring in an overtension state detrimental to its conservation. Such blocking devices require for their mounting the positioning or assembly of three pieces or members, the setting of one of which, of the spring wire, being particularly difficult, so that its mounting has to be executed manually by workers trained for this kind of work.

Accordingly it is a primary object of the present invention to provide a new device for unidirectionally blocking a ratchet wheel yielding such results.

Another object of the present invention is to provide a device for unidirectionally blocking a ratchet wheel, which allows a certain return travel of said ratchet wheel before the blocking of said ratchet wheel, whereby to avoid to maintain the motor or main spring in an overtension state detrimental for the conservation of such main spring.

A further object of the present invention is to provide a device for unidirectionally blocking a ratchet wheel, which allows a return travel of said ratchet wheel foregoing to the blocking of the ratchet wheel amounting to at least twice the pitch of the toothing of said ratchet wheel.

Still another object of the present invention is to provide a device for undirectionally blocking a ratchet wheel in which the amount of the return travel of the ratchet wheel before the blocking of said ratchet wheel is easily adjustable in certain limits. 1

A further object of the present invention is to provide a device for unidirectionally blocking a ratchet wheel, which is subjected to very small working stresses so as to avoid breaking risks.

' A still further object of the present invention is to provide a device for unidirectionally blocking a ratchet wheel, the operation of which is silent and soft or smooth.

Another object of the present invention is to provide a device for unidirectionally blocking a ratchet wheel, which is apt to be mounted by means of automatic mounting or assembling means or equipment, said device comprising merely a unique blocking organ or member.

A still other object of the present invention is to provide a device for unidirectionally blocking a ratchet wheel, the positioning of which in a recess is sufficient for its mounting.

A further object of the present invention is to provide a device for unidirectionally blocking a ratchet wheel, which is automatically maintained in its axial mounting position by means of said ratchet wheel as soon as the ratchet wheel has been fixed on the barrel arbor of the watch movement comprising said device.

A still further object of the present invention is to provide a device for unidirectionally blocking a ratchet wheel, which comprises a unique movable member comprising retaining means co-operating with a stop means and a tooth and a disengaging means both co-operating with the toothing of said ratchet wheel.

Various other more detailed objects and advantages of the invention, such as arise in connection with carrying out the invention in practical embodiments, will be in part obvious, and in part be hereinafter stated as the description of the invention proceeds.

For a full and more complete understanding of the invention reference may be had to the following description and accompanying drawings wherein:

FIG. 1 is a view in elevation of an embodiment of the device of the present invention;

FIG. 2 is a sectional view according to line llll of FIG. 1;

FIG. 3 is asectional view according to line III-III of FIG. 1;

FIGS. 4, 5 and 6 are partial top views showing three working positions of the device of FIGS. 1-3; and

FIGS. 7 and 8 are top views showing two slightly modified variants of the device of FIG. 1.

In FIG. 1 wheel 1 is the ratchet wheel of a watch movement. Square opening 2 of wheel 1 is intended to be mounted on a (not shown) male square of the barrel arbor of said watch movement. Barrel bar 3 extends under wheel 1 and presents a circular recess 4 for receiving said ratchet wheel I and a second recess 5 for receiving a blocking organ or member 6, recess 5 being deeper than recess 4. Blocking member 6 is made up of a cranked or bent lever shaped blanked piece milled for having two bosses or bossages 7 and 8 connected to each other by means of a narrow elastic slightly incurvate arm 9. Cranked or bent portion 10 and second arm 11 of member or organ 6 have constant thicknesses. Arm 11 has in its outer edge a round shaped or rounded off projection 12 and at one of its ends a circular head 13.

Arm 9 and bosses or bossages 7 and 8 extend at the periphery of ratchet wheel 1 along a segment of about 45. Arm 11 is located below ratchet wheel 1, circular head 13 being engaged in a cylindrical space or bed adjacent to recess 5 for affording pivoting movement of organ or member 6 around of the axis of circular head 13. This pivoting axis is located between the axis of ratchet wheel 1 and the toothed ratchet wheel segment extending between bosses or bossages 7 and 8. A slight dip or depression 14 in a flank of recess 5 corresponds to rounded off projection 12 for forming a stop or abutment for blocking organ or member 6.

Bossage 7 is blanked for having in its inner edge a slightly asymmetrical tooth 15 apt to engage toothing 16 of ratchet wheel 1. Boss or bossage 8 has an annular form, its internal face being turned against toothing 16 of ratchet wheel 1 and extending along the prolongation of the the inner edge of arm 9. Opening 17 formed or cut in bossage 8 is accessible from above barrel bar 3, since said bossage 8 extends adjacent toothing 16 of ratchet wheel 1.

FIG. I shows the radius of the arcs described by tooth l5 and bossage 8 at the time of the pivoting of organ 6 around of the axis of head 13 being smaller than the radius of ratchet wheel I.

The position of organ 6 shown in full lines in FIG. 1 corresponds approximately to the position of this organ 6, in which it blocks ratchet wheel 1. More exactly, said position of organ 6 shown in full lines in FIG. 1 corresponds to the position obtained at the moment of commencing to drive ratchet wheel 1 in the direction of arrow 18 for energizing or winding the motor or main spring (not shown) of the watch movement comprising said ratchet wheel. In the blocking position proper the ratchet wheel tooth located immediately before or in front of tooth 15 of organ 6 in the direction opposite to the direction of arrow 18 leans up against last-mentioned tooth 15, whereby to urge organ 6 to pivot in the direction opposite to the direction of arrow 18 and to push or press rounded off projection 12 against the flank of dip or depression 14 of barrel bar 3.

When turning the winding button or crown (not shown) of the watch movement comprising ratchet wheel 1 for driving or rotating said wheel 1 in the direction of arrow 18, the tooth of toothing 16 located behind tooth 15 tends to make blocking organ 6 pivot in the direction of arrow 18. Thus the position shown in FIG. 4 and the position shown in FIG. 5 are successively reached or obtained. A comparison of FIGS. 4 and 5 shows that organ 6, when pivoting around of its axis of pivotment, displaces tooth 15 for disengaging tooth 15 from toothing 16 of ratchet wheel 1, while it displaces bossage 8 for causing bossage 8 to progressively engage said toothing 16. When the position shown in FIG. 5 is reached, toothing 16 of ratchet wheel 1 engages the internal face of bossage 8.

From this moment on two working or operating states or region can be distinguished according to a slow or fast rotation of ratchet wheel 1 of the described device.

In case of slow rotation of ratchet wheel 1, toothing 16 of ratchet wheel 1 engages simultaneously tooth l5 and said intemal face of boss or bossage 8, the top of tooth passing on the top of a tooth of toothing 16 of ratchet wheel 1 (position of organ 6 shown in dash-dotted line in FIG. 1) and organ 6 returning under the influence of the elasticity of arm 9 and of the pression of toothing 16 on bossage 8 to its position shown in FIG. 5. This working or operating cycle is repeated at every passage of tooth 15 on a tooth of toothing 16 of ratchet wheel 1, boss or bossage 8 acting obviously as a means or element for disengaging tooth 15 from toothing 16 under the influence of elastic arm 9.

In case of fast rotation of ratchet wheel 1 boss or bossage 8 acts again as a means or element for disengaging tooth 15 from toothing 16 of ratchet wheel 1, but in a slightly different manner. For, under the influence of the inertia of organ 6 as well as under the influence of the friction of toothing 16 of ratchet wheel 1 against said internal face of bossage 8 of organ 6, said organ 6 takes the position shown in FIG. 6, the teeth of toothing 16 passing below tooth 15 of organ 6 without contacting or engaging said tooth 15 of organ 6.

As soon as the winding button or crown is no more rotated, the main or motor spring urges or causes ratchet wheel 1 to rotate in the direction opposite to the direction of arrow 18. Said internal face of disengaging element or bossage 8 of blocking organ 6 being still engaged with toothing 16 of ratchet wheel 1 independently of the ratchet wheel driving or winding having been slow or fast, disengaging element or bossage 8 is led or driven away by toothing 16 in any case and, while simultaneously disengaging toothing 16, causes or provokes a pivotment or pivoting movement of blocking organ 6 in the direction of the rotation of ratchet wheel 1, which, as mentioned above, is the direction opposite to the direction of arrow 18. Therefore, tooth 15 of blocking organ 6 is forced to engage toothing 16 of ratchet wheel 1, blocking organ 6 being restored or reconducted to its position shown in FIG. 1, this position being the position of blocking ratchet wheel 1 by means of the pression of one of the teeth of toothing 16 of ratchet wheel 1 on the right hand flank of tooth 15 of blocking organ 6. Opening 17 of disengaging element or bossage 8 allows to entirely slacken or disenergise the barrel spring. For doing this, it is sufficient to turn or rotate the winding button or crown in the winding direction and simultaneously seize or take up disengaging element or bossage 8 by means of a point engaged in opening 17 so as to disengage or move apart disengaging element or bossage 8 from toothing 16 of ratchet wheel 1. Disengaging element or bossage 8 and tooth 15 of blocking organ 6 are then simultaneously disengaged or separated from toothing 16 of ratchet wheel 1, so that ratchet wheel 1 is set free or released.

FIG. 1 shows a slightly modified embodiment of the present invention, in which embodiment blocking organ 26 has a plan view forme analogous or similar to that of blocking organ 6. Elastic arm 29 extends outside of toothing 16 of ratchet wheel 1. However, boss or bossage 27 shows a greater length than bossage 7 shown in FIG. 1. Bossage 27 extends beyond tooth 35 in the direction of cranked or bent portion 30 of blocking organ 26. The internal edge or face 28 of bossage 27 has the forme of a cylindrical surface coaxial with ratchet wheel 1, so that in the blocking position of blocking organ 26 shown in FIG. 7 said edge or face 28 of bossage 27 leans up against the tops of three adjacent teeth of toothing 16 of ratchet wheel 1. Thus the blocking of ratchet wheel 1 is effectively realized by means of edge or face 28, tooth 35 only causing blocking organ 26 to return in its position for blocking ratchet wheel 1.

In the above embodiment of FIG. 7 second arm 31 of blocking organ 26 has a rectilinear or straight external edge.

The embodiment shown in FIG. 8 of the present invention works in a way similar to that of the embodiment shown in FIG. 1, blocking organ 46 differing from organ 6 only in elastic arm 49 being cranked or bent so as to extend below toothing 16 of ratchet wheel 1, the position of blocking organ 46 shown in FIG. 8 corresponding to the position of organ 46, in which position organ 46 causes the blocking of ratchet wheel 1.

The blocking organ described above presents several advantages relative to prior art pawl and spring ratchet or blocking devices.

It is indeed highly desirable, that blocking devices of barrel ratchet wheels allow a certain return travel of said ratchet wheel before the blocking of said ratchet wheel, whereby to avoid to maintain the main or motor spring at a maximum tension, such maximum tension being detrimental for the conservation of said main or motor spring. Now an important and highly desirable advantage of the blocking device described above resides in the amount or length of the return travel of ratchet wheel 1 before the blocking of ratchet wheel 1 amounting to at least twice the pitch of toothing 16 of ratchet wheel 1 on account of the manner of the return travelling of blocking organ 6, 26, 46 to its blocking position, such amount of return travel of ratchet wheel 1 being therefore adjustable in certain limits and obtained at the very small deformation (position in dash dotted line of blocking organ 6 in FIG. 1) of elastic arm 9, 29, 49 of blocking organ 6, 26, 46 necessary for disengaging disengaging element or bossage 8 of said organ 6, 26, 46 from toothing 16 of ratchet wheel 1. Further, elastic arm 9, 29, 49 being subjected to only very small stresses, there is no risk or danger of breaking of elastic arm 9, 29, 49 to be taken in consideration or to fear. Morover, working or operation of the described blocking device is silent, smooth and soft.

Another very important advantage of the described blocking device resides in its unique movable blocking organ 6, 26, 46 being apt to be mounted by means of automatic mounting or assembling installations or equipment. The described blocking device comprises, indeed, only one such organ, the positioning or introduction of this organ 6, 26, 46 in recess 5 provided for its reception being sufiicient for completing the mounting of said organ 6, 26, 46 in the watch movement comprising the ratchet wheel to be unidirectionally blocked by said organ. Since a portion of blocking organ 6, 26, 46 extends under ratchet wheel 1, blocking organ 6, 26, 46 is automatically maintained or hold in its axial mounting position as soon as ratchet wheel 1 has been fixedon the barrel arbor of the watch movement.

What is claimed is:

1. In a watch movement comprising a barrel having a barrel bar and a ratchet wheel, a blocking device comprising a unique movable member for unidirectionally blocking said ratchet wheel, said unique movable member being partly embedded in a recess disposed in said barrel bar for pivoting around of an axis parallel to the axis of said ratchet wheel and comprising on the one hand an incurvated lateral surface portion having the form of a circular arc, the radius of which is equal to the radius of the circle defined by the tops of the teeth of said ratchet wheel, said incurvated lateral surface portion being directed so as to simultaneously lean up against several teeth of said ratchet wheel, when said unique movable member is in its blocking position, and, on the other hand, a tooth and a disengaging means both co-operating with the toothing of said ratchet wheel, a portion of a flank of said recess forming said stop means.

2. In a watch movement comprising a barrel having a barrel bar and ratchet wheel, a blocking device comprising a unique movable member for unidirectionally blocking said ratchet wheel, said unique movable member being partly embedded in a recess disposed in said barrel bar for pivoting around of an axis parallel to the axis of said ratchet wheel and comprising on the one hand a retaining means cooperating with a stop means and, on the other hand, a tooth and a disengaging means both cooperating with the toothing of said ratchet wheel, a portion of a flank of said recess forming said stop means, said tooth and said disengaging means of said unique movable member being so disposed relative to said pivoting axis of this member, that one of them engages the toothing of said ratchet wheel when the other one disengages the toothing of said ratchet wheel and vice versa according to the pivoting direction of said unique movable member.

3. A device according to claim 2 in which said pivoting axis of said unique movable member is disposed between the axis of said ratchet wheel and a toothed segment of this ratchet wheel extending between the locations where said tooth and said disengaging means of said unique movable member engage the toothing of said ratchet wheel, the diameters of the arcs forming the displacement paths defined by the pivoting movements of said tooth and of said disengaging means at the time of a pivoting movement of said unique moveable member being smaller than the diameter of said ratchet wheel.

4. In a clockwork movement comprising a ratchet wheel, a blocking device comprising a unique movable member for unidirectionally blocking said ratchet wheel, said unique movable member being disposed for pivoting around of an axis parallel to the axis of said ratchet wheel and. comprising on the one hand an incurvated lateral surface portion having the fonn of a circular arc, the radius of which is equal to the radius of the circle defined by the tops of the teeth of said ratchet wheel, said incurvated lateral surface portion being directed so as to simultaneously lean up against several teeth of said ratchet wheel, when said unique movable member is in its blocking position, and, on the other hand, a tooth and a disengaging means both co-operating with the toothing of said ratchet wheel.

5. A device according to claim 4 in which said disengaging means comprises an opening for allowing disengaging of said unique movable member from the toothing of said ratchet wheel for releasing said ratchet wheel.

6. In a clockwork movement comprising a ratchet wheel, a blocking device comprising a unique movable member for unidirectionally blocking said ratchet wheel, said unique movable member being disposed for pivoting around of an axis parallel to the axis of said ratchet wheel and comprising on the one hand a retaining means cooperating with a stop means, and, on the other hand, a tooth and a disengaging means both cooperating with the toothing of said ratchet wheel, said tooth and said disengaging means of said unique movable member being so disposed relative to said pivoting axis of this member, that one of them engages the toothing of said ratchet wheel when the other one disengages the toothing of said ratchet wheel and vice versa according to the pivoting direction of said unique movable member.

7. A device according to claim 6 in which said pivoting axis of said unique movable member is disposed between the axis of said ratchet wheel and the toothed segment of this ratchet wheel extending between the locations where said tooth and said disengaging means of said unique movable member engage the toothing of said ratchet wheel, the diameters of the arcs forming the displacement paths defined by the pivoting movements of said tooth and of said disengaging means at the time of a pivoting movement of said unique movable member being smaller than the diameter of said ratchet wheel. 

1. In a watch movement comprising a barrel having a barrel bar and a ratchet wheel, a blocking device comprising a unique movable member for unidirectionally blocking said ratchet wheel, said unique movable member being partly embedded in a recess disposed in said barrel bar for pivoting around of an axis parallel to the axis of said ratchet wheel and comprising on the one hand an incurvated lateral surface portion having the form of a circular arc, the radius of which is equal to the radius of the circle defined by the tops of the teeth of said ratchet wheel, said incurvated lateral surface portion being directed so as to simultaneously lean up against several teeth of said ratchet wheel, when said unique movable member is in its blocking position, and, on the other hand, a tooth and a disengaging means both co-operating with the toothing of said ratchet wheel, a portion of a flank of said recess forming said stop means.
 2. In a watch movement comprising a barrel having a barrel bar and ratchet wheel, a blocking device comprising a unique movable member for unidirectionally blocking said ratchet wheel, said unique movable member being partly embedded in a recess disposed in said barrel bar for pivoting around of an axis parallel to the axis of said ratchet wheel and comprising on the one hand a retaining means cooperating with a stop means and, on the other hand, a tooth and a disengaging means both cooperating with the toothing of said ratchet wheel, a portion of a flank of said recess forming said stop means, said tooth and said disengaging means of said unique movable member being so disposed relative to said pivoting axis of this member, that one of them engages the toothing of said ratchet wheel when the other one disengages the toothing of said ratchet wheel and vice versa according to the pivoting direction of said unique movable member.
 3. A device according to claim 2 in which said pivoting axis of said unique movable member is disposed between the axis of said ratchet wheel and a toothed segment of this ratchet wheel extending between the locations where said tooth and said disengaging means of said unique movable member engage the toothing of said ratchet wheel, the diameters of the arcs forming the displacement paths defined by the pivoting movements of said tooth and of said disengaging means at the time of a pivoting movement of said unique moveable member being smaller than the diameter of said ratchet wheel.
 4. In a clockwork movement comprising a ratchet wheel, a blocking device comprising a unique movable member for unidirectionally blocking said ratchet wheel, said unique movable member being disposed for pivoting around of an axis parallel to the axis of said ratchet wheel and comprising on the one hand an incurvated lateral surface portion having the form of a circular arc, the radius of which is equal to the radius of the circle defined by the tops of the teeth of said ratchet wheel, said incurvated lateral surface portion being directed so as to simultaneously lean up against several teeth of said ratchet wheel, when said unique movable member is in its blocking position, and, on the other hand, a tooth and a disengaging means both co-operating with the toothing of said ratchet wheel.
 5. A device according to claim 4 in which said disengaging means comprises an opening for allowing disengaging of said unique movable member from the toothing of said ratchet wheel for releasing said ratchet wheel.
 6. In a clockwork movement comprising a ratchet wheel, a blocking device comprising a unique movable member for unidirectionally blocking said ratchet wheel, said unique movable member being disposed for pivoting around of an axis parallel to the axis of said ratchet wheel and comprising on the one hand a retaining means cooperating with a stop means, and, on the other hand, a tooth and a disengaging means both cooperating with the toothing of said ratchet wheel, said tooth and said disengaging means of said unique movable member being so disposed relative to said pivoting axis of this member, that one of them engages the toothing of said ratchet wheel when the other one disengages the toothing of said ratchet wheel and vice versa according to the pivoting direction of said unique movable member.
 7. A device according to claim 6 in which said pivoting axis of said unique movable member is disposed between the axis of said ratchet wheel and the toothed segment of this ratchet wheel extending between the locations where said tooth and said disengaging means of said unique movable member engage the toothing of said ratchet wheel, the diameters of the arcs forming the displacement paths defined by the pivoting movements of said tooth and of said disengaging means at the time of a pivoting movement of said unique movable member being smaller than the diameter of said ratchet wheel. 